Assembly of elements for making intermittent electrical contact



Feb. 2, 1965 J. P. GEBHART 3,168,635

ASSEMBLY OF ELEMENTS FOR MAKING INTERMITTENT ELECTRICAL CONTACT FiledDec. 31, 1962 Er .10 11 -.5

i I JII I I i 3 r r. 1 ZIIIIIIHI MIL 9 mnoi I/ (Q INVENTOR. i time196554427 Irraevss tact'siare involved in the United States Patent FiledDec. 31,1962, Ser. No. 243,791

7 Claims. 01. 200-166 This invention relates to electrical contacts andparticularly to intermittent electrical contact elements which providesubstantially one hundred percent reliability.

lIn.U.S. patent application, Serial. No. 57,832, filed September 22,1960, entitled Tape Program Apparatus,

now Patent No. 3,071,317, issued January 1, 1963, and

assigned to. the sameassignee as the present application, a readoutsystem is disclosed and claimed. This system utilizes two groups of aplurality of electrical contacts, one group of which is movablesimultaneously toward the other grou Contact being made between oppositeele ments onlywhen a perforation appears in a film or tape positionedtherebetween. Although the contact element's shown. in the patentedsystem have good reliability, greater reliability is desired, especiallywhenmanyelectrical con aiid complex circuitry. 3 4 I l i e,

The present invention, therefore, ,is directed .to an electrical contactarrangement which may be used in the apparatusshown in I the ab'ov'ementioned patent with substantially one hundred percent reliability.This reliability is provided by using a plurality of knife edgesarranged in a circle which are adapted to beficontacted by the slopingsides of almovabl tapered element. e

Reliability is obtainable eventhough there isa certain amount ofeccentricity between the axisof the tapered element and the axis of theknife edges. Furthermore, the use ofknife edges provides the minimum ofjarea exposable to dirt and dust, and even though dirt and dust maycollect on the. tapered surfaces, the knife edges can readily penetratethrough the dirt and dust to insure a good contact.

A combination of contact elements for use with continuously movingperforated film or tape and having a high degree of reliability is alsodescribed hereinafter.

The principal object of the invention, therefore, is to provide theoptimum of reliability in the making of intermittent electricalcontacts.

testing of complicated systems Another object of the invention is toprovide an improved contact construction between two electricalconducting elements. N

A further object ofthe invention is to provide an improved rollingelectrical contact construction.

A still further object of the invention is to provide an improvedintermittent electrical contact construction which providessubstantially one hundred percent reliability.

A better understanding of this invention may be had from the followingdetailed description when read in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a side view, partly in cross-section, of a pair of electricalcontact elements embodying the invention;

FIG. 2 is an enlarged cross-sectional view showing two contact elementsin contact;

FIG. 2a is a cross-sectional view taken along the line 2a2a of FIG. 2;

FIG. 3 is a perspective view, partly incross-section, showing themovable contact element;

FIG. 4 is a perspective view, showing the fixed contact element;

FIG. 5 is a perspective view, partly in cross-section, showing a rollingcontact element for continuously moving tape or film;

. 6 is aperspective view, partly in cross-section, of

the contactor for the element shown in FIG. 5; and

FIG. 7 is a cross-sectional view taken with the rolling contact shown inFIG. 5 and the contactor of FIG. 6 in engagement. 1 6

Referring, now, to the drawings in which the, same numerals identify thesame elements, a-fixed block 5 of these elements can be mounted asdescribed in the above-mentioned patent.

A mounting block 14 adapted to be oscillated in the direction of thearrow 15 mounts a pair of contact elements shown generally at 16 and17,movement of the block 14 bringing the contact elements 16 and 17 incontact with the fixed contact elements 6and 7. The elements 16 and 17may. be insulated from the block 14 by, e

21, or the block maybe of insulatinsulations 20 and ing material.

Shown passing between the contact elements 6-7 and 16-17 is a filmortape23 which has been. perforated in a prearranged order to permit certainof opposing con-. tact elements to contact each other when a perforationappears between them. If no perforation is present, thenthetips of thecontacts film or .tape and; no contactis made.1 e

a The details of the fixed contact elements are shown. in FIGS. 2,2a,.and {1, the fixed contactors such as 6 and 7 having a cross-notchedplate 25 attached to a-cylindr icalbody seetion 26,;having an end cavity27 in which the end .ofan electrical conductor may be soldered. Bycross-notching plate 25, four centrally arranged parallel knife edges30are provided, a practicalfplate having a thickness of 5/ of an inch, anotch widthof 9 of an inch, while the diameter. of thebody 26 is ofaninch. i I it Each o f the movable contact elements such as shown -at16 and 17 and in detail in FIG. 3 has a hollow cylindrical body 32 of ofan inch diameter. Near the end of the body is a flange 33 of a thicknessof of an inch and through which passes a cylindrical element 34 having atapered conical tip surface 35 and a flat tip surface 36. The innersection of the cylinder 34 has a flange 39, while the end of thecylinder has mounted thereon a compression spring 40, the other end ofthe spring 40 abutting an electrical connecting element 41. Thus, thecylinder 34 is biased outwardly by the spring 40. The dimensions of atypical contact element such as shown in FIG. 3 are those in which thecylinder 34 is of an inch in diameter, the diameter of the surface ofthe tip 36 is of an inch, while the angle of the tapered surface 35 withrespect to the surface of the cylinder 34 is 45 degrees. I

As shown in FIGS. 2 and 2a,-when a perforation appears in the tape 23,the tapered surface 35 is brought into contact with one or more of theknife edges 30 of the plate 25 when the block 14 is moved toward theblock 5. As shown in FIG. 2a, the axis of the tapered portion 35 isconcentric with the circle of the knife edges 30. However, if a certaineccentricity should exist, the surface 35 may only contact one ortwo ofthe knife edges but this contact is sufiicient to provide the desiredelectrical connection. Since the cylinder 34 is under the compression ofthe spring 40, no damage is done to the contacting surface if someeccentricity exists.

As mentioned above, since the knife edges have prac-' tically noappreciable surface on which dust or dirt can collect, and if any dustor dirt should exist on the tapered surface 35, it will be easilypierced by the sharp knife edges 30.

Patented Feb. 2, 1965 16 and,17 rest against the 'In FIG. 5, theconstruction of one element of a rolling type of contact system forcontinuouly moving film or tape is shown. This element includes a roller50 mounted on a shaft 51 in a yoke 52 which has a pin 54 therethrough,the ends of the pin being in slots 55"and 56 in a cylindrical body 60.The roller 60 is under tension of a spring 61 having one end against theyoke 52 and the other end against an electrical connecting element 62fastened to the body 60. Thus, the roller 50 may roll along on the filmuntil a perforation is reached, at which time the-contact roller 50 mayconnect the special contacting element shown in FIGS. 6 and 7. Theelement shown in FIGS. 6 and 7 has'a cylindrical body 43 and anelectrical connecting element 44 which is threaded to the body 43 inorder to vary the tension of-a spring 45, one end of which abuts thecontact element 46. The end of body 43 has a flange 63, the centralopening for the element 46 being chamfered as shown at 64. The normalposition of the tapered end of element 46 is such that its tip surfaceis in the outer plane of flange 63, a flange 66 on element 46 abutting ashoulder of body 43 to hold the element 46 in position. Now, the spring61 of the roller element shown in FIG. is stronger than the spring 45 ofthe element shown in FIG. 6 so that when the roller 50 encounters aperfora tion, it first makes contact with the flat tip of element 46 andthen depresses element 46 to make contact with the chamfered surface 64,as shown at 50". This action pro- ,vides double insurance of agoodcontact being made.

Iclaim: I 1. An electrical contact assembly comprising a fixedelement'and a movable element adapted to be intermittently brought intocontact with said fixed element, one

i of said elements having at least one knifeedge contacting surface andthe other of said elements having a tapered surface for contacting saidknife edge surface, said fixed element being a plate havingv crossnotches therein to form a plurality of parallel knife edge surfacesconcentrically positioned.

4 surface for contacting said knife edge surface, said movable elementbeing a cylinder having a tapered conical surface at the end thereof,the axis of said cylinder being substantially concentric with the axisof said concentrically positioned knife edge surfaces.

3. A pair of electrical contact elements adapted, to make contactintermittently comprising one'fixed element and one movable element, oneof said elements having a contactor plate with crossed notches over thesurface thereof to provide a plurality of parallel knife edge surfacesand the other of said elements having a tapered conical surface withrespect to the surface of said firstmentioned element, said taperedsurface and said knife edge surfaces being brought into contact uponmovement of said movable element.

4. A pair of electrical contact elements in accordance with claim 3 inwhich means are provided for resiliently biasing one of said contactelements toward the other of said contact elements. I

5. A pair of electrical contact elements in accordance with claim 3 inwhich said movable contact element includes a hollow cylindrical bodyand a cylinder passing through one end of said body, the end of saidcylinder having its outer surfacetapering toward the axis of saidcylinder. 7 g

6. A pair of electrical contact elements in accordance with claim 5 inwhich said cylinder is resiliently biased toward said fixed element.

7. A pair of electrical contact elements in accordance withclaim 6 inwhich said parallel knifeedge surfaces are concentrically positioned. I

References Cited by the Examiner v UNITED STATES PATENTS 2,339,996

1/44 Kight 20019' 2,753,432 7/56 Long et a1. 200l66 2,931,874 4/60Leaman 200 6l.08 X 2,934,628 4/ Massar etal ZOO-1 17 X 3,002,061 9/ 61Perkins 20046 3,032,620 5/62 Siiberg 200l66 3,047,682 7/62 Hults 200l66BERNARD A. GILHEANY, Primary Examiner.

1. AN ELECTRICAL CONTACT ASSEMBLY COMPRISING A FIXED ELEMENT AND AMOVABLE ELEMENT ADAPTED TO BE INTERMITTENTLY BROUGHT INTO CONTACT WITHSAID FIXED ELEMENT, ONE OF SAID ELEMENTS HAVING AT LEAST ONE KNIFE EDGECONTACTING SURFACE AND THE OTHER OF SAID ELEMENTS HAVING A TAPEREDSURFACE FOR CONTACTING SAID KNIFE EDGE SURFACE, SAID FIXED ELEMENT BEINGA PLATE HAVING CROSS NOTCHES THEREIN TO FORM A PLURALITY OF PARALLELKNIFE EDGE SURFACES CONCENTRICALLY POSITIONED.